Unlikely extremely painful accidents that make you afraid

[TreyWilly]

I think we should all share the accidents (real or fabled) that haunt us. These should be painful enough on both a physical and psychological level so that the mere mention of one makes us cringe.

Mine:

Every time I have to lower the toilet seat to crap, I think about how awful it would be if my balls got caught between the toilet and the seat at the same time I sat down, crushing my testicles under the weight of my own ass.

This is unlikely, perhaps impossible, but it owns me.

What is yours? In the words of Will Hunting, "Let's let the healing begin."